Instructables

solar panels of different voltage (.5 off)


made a usb charger and have 3 solar panels to use.

1x   5.5v 320ma
2x  6v 250ma

right now i have them in parallel charging my usb device. 

do the 6v panels draw current away from the 5.5v?

would it be more efficient to just use the 6v's?

They are all driving if you are getting a current reading on your meter.

As long as you have a diode on each solar panel isolating the panel and stopping feedback they will all drive current when needed.

If the panels are identical other than the voltage it sounds like the one solar panel may have a diode and the others don’t or the one solar panel has a different diode.

A 1N4001 diode has a voltage drop of 1 volt.

A 1N5817 diode has a voltage drop of .5 volts.

If this is the case you can change the diodes to make the panels more efficient however it should not be necessary for them to work.